CVE-2025-40233 Details
Description
In the Linux kernel, the following vulnerability has been resolved: ocfs2: clear extent cache after moving/defragmenting extents The extent map cache can become stale when extents are moved or defragmented, causing subsequent operations to see outdated extent flags. This triggers a BUG_ON in ocfs2_refcount_cal_cow_clusters(). The problem occurs when: 1. copy_file_range() creates a reflinked extent with OCFS2_EXT_REFCOUNTED 2. ioctl(FITRIM) triggers ocfs2_move_extents() 3. __ocfs2_move_extents_range() reads and caches the extent (flags=0x2) 4. ocfs2_move_extent()/ocfs2_defrag_extent() calls __ocfs2_move_extent() which clears OCFS2_EXT_REFCOUNTED flag on disk (flags=0x0) 5. The extent map cache is not invalidated after the move 6. Later write() operations read stale cached flags (0x2) but disk has updated flags (0x0), causing a mismatch 7. BUG_ON(!(rec->e_flags & OCFS2_EXT_REFCOUNTED)) triggers Fix by clearing the extent map cache after each extent move/defrag operation in __ocfs2_move_extents_range(). This ensures subsequent operations read fresh extent data from disk.
A vulnerability in the Linux kernel's OCFS2 file system can lead to a stale extent map cache when extents are moved or defragmented. This issue causes subsequent operations to encounter outdated extent flags, triggering a BUG_ON condition in the 'ocfs2_refcount_cal_cow_clusters()' function. The problem arises when the 'copy_file_range()' function creates a reflinked extent marked as 'OCFS2_EXT_REFCOUNTED'. Following this, the 'ioctl(FITRIM)' command activates the 'ocfs2_move_extents()' function, which reads and caches the extent flags. However, the extent map cache is not invalidated after the move, leading to a mismatch between the cached flags and the updated flags on disk. This discrepancy causes a BUG_ON condition to trigger, indicating a critical error that could disrupt normal operations.
The vulnerability has been addressed by modifying the 'ocfs2_move_extents_range()' function to clear the extent map cache after each move or defragment operation. This change ensures that subsequent operations read the most current extent data from the disk.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Dec 4, 2025References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://git.kernel.org/stable/c/78a63493f8e352296dbc7cb7b3f4973105e8679e | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/93166bc53c0e3587058327a4121daea34b4fecd5 | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/93b1ab422f1966b71561158e1aedce4ec100f357 | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/a21750df2f6169af6e039a3bb4893d6c9564e48d | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/a7ee72286efba1d407c6f15a0528e43593fb7007 | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/aa6a21409dd6221bb268b56bb410e031c632ff9a | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/bb69928ed578f881e68d26aaf1a8f6e7faab3b44 | kernel.org | Source CodeVendor |
| https://git.kernel.org/stable/c/e92af7737a94a729225d2a5d180eaaa77fe0bbc1 | kernel.org | Source CodeVendor |
Weakness Enumeration
No weakness enumeration is available for this CVE.
Affected Products
| Product | Versions |
|---|---|
| Linux kernel | All versions |
CPE
Remediation
| |
| Linux ocfs2 | All versions |
CPE
Remediation
| |
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 30, 2026 | CVE Modified | kernel.org |
| Jun 17, 2026 | CVE Modified | kernel.org |
| Dec 4, 2025 | New CVE Received | kernel.org |